Use of norbornane derived compounds as threshold agents

ABSTRACT

A process of preventing precipitation of scale producing metal ions, e.g. calcium, from their aqueous solutions by adding an effective amount of a methylenephosphonic acid derivative of bis(methylamine)-norbornane. These compounds are effective in threshold amounts.

This is a divisional of application Ser. No. 584,071, filed Feb. 27,1984, now U.S. Pat No. 4,500,469.

BACKGROUND OF THE INVENTION

Norbornane is a cyclic compound found in or derivable from the residualheavy hydrocarbons in the bottoms of distillation towers in lighthydrocarbon production facilities. Various derivatives of norbornanehave been made, among them the bis(methylamine). It is this compoundwhich has been phosphonomethylated which is the subject of the presentinvention.

It is well known that amines such as ethylenediamine anddiethylenetriamine can be reacted with formaldehyde and phosphorus acidto obtain methylene phosphonate derivatives of the amine in which themethylene phosphonate group ##STR1## substitutes for the amine hydrogens(U.S. Pat. No. 3,288,846).

The use of methylenephosphonic acid substituted alkylene polyamines formetal ion control at less than stoichiometric amounts was suggested in apatent (U.S. Pat. No. 2,609,390) issued in 1952. Later a waterdispersible polymeric amine chelating agent which included alkylenephosphonate derivatives was indicated as having "threshold" effects inscale inhibition applications (see U.S. Pat. No. 3,331,773), this termbeing used to describe the use of the agent in less than stoichiometricamounts. The diamine and polyamine methylenephosphonate derivatives aretaught and claimed in U.S. Pat. Nos. 3,336,221 and 3,434,969,respectively. Some of the products disclosed in these two patents areavailable commercially and are recommended as scale inhibitors whenapplied in threshold amounts.

Other patents which disclose heterocyclic nitrogen containing compoundswhich are useful as chelating agents and may be employed in thresholdamounts are U.S. Pat. Nos. 3,674,804; 3,720,498; 3,743,603; 3,859,211;and 3,954,761. Some of the compounds included therein are heterocycliccompounds having the formulas: ##STR2## wherein R is hydrogen or alkyland M is hydrogen, alkali metal, ammonium or a di- or triethanolamineradical; ##STR3##

Certain phosphonic acid derivatives of the aliphatic acids can beprepared by reacting phosphorous acid with acid anhydrides or acidchlorides, e.g. the anhydrides or chlorides of acetic, propionic andvaleric acids. The compounds prepared have the formula ##STR4## whereinR is a lower alkyl radical having 1 to 5 carbon atoms. The method ofmaking and use of these products is described in U.S. Pat. No.3,214,454. The use of threshold amounts to prevent calcium precipitationis disclosed and claimed therein.

It has now been discovered that new chelating and threshold agents forinhibiting precipitation of metal ions can be made from thebis(methylamine) derivatives of norbornane. This compound has thestructure ##STR5##

This compound is also known by the more formal name of 2(3),5(6)-bis[aminomethyl]bicyclo(2,2,1)heptane. Its derivatives are thosewith various substituents replacing the primary amine hydrogens.

SUMMARY OF THE INVENTION

A new class of compounds is formed when norbornane bis(methylamine) isreacted with certain compounds, e.g. formaldehyde and phosphorous acidwill form methylenephosphonic acid derivatives. These new compounds havethe structure ##STR6## wherein substituents A, B, X and Y each areindependently selected from radicals consisting of hydrogen,hydroxyalkyl (wherein the alkyl group contains 2-6 carbon atoms),methylenephosphonic, methylene-, ethylene- and propylenesulfonic2-hydroxypropylsulfonic and carboxylic acid radicals (having 2-4 carbonatoms) and the alkali or alkaline earth metal, ammonia and amine saltsof any of the phosphonic, sulfonic or carboxylic acid derivatives. Atleast one of the substituents must be other than a hydrogen.

DETAILED DESCRIPTION OF THE INVENTION

The following examples illustrate the preparation and use of the newcompounds of the invention. Identification of the compounds is made byreference to the above structure.

EXAMPLE 1

Distilled water (10 g) and H₃ PO₃ (9.9 g) were weighed into a 50-mlround-bottom flask equipped with a water-cooled condenser, athermometer, a stirring bar, and an addition funnel. Concentrated HCl(11.8 g) was then added and 3.9 g of2(3),5(6)bis[aminomethyl]bicyclo(2,2,1)heptane was slowly added whilestirring. The solution was heated at reflux for approximately one hourand a 37% aqueous formaldehyde solution (8.51 g) was added over a periodof 2.5 hours. The solution was heated for an additional 3 hours atreflux. The compound formed was the completely phosphonomethylatednorbornane derivative wherein each of A, B, X and Y weremethylenephosphonic acid groups, --CH₂ PO₃ H₂.

EXAMPLE 2

The procedure for Example 1 was followed for the addition of 3 moleequivalents of CH₂ O (24.3 g of a 37% solution) and phosphorous acid(25.1 g) to one mole equivalent of2(3),5(6)bis[aminomethyl]bicyclo(2,2,1)heptane (15.2 g). The resultantsolution was neutralized with NaOH (aq) and one mole equivalent ofglycolonitrile (14.7 g of a 38% solution) and NaOH (13.8 g of a 33.3%solution) was added. The compound formed was the sodium salt of thebicycloheptane derivative which had an average of threemethylenephosphonic acid groups and one carboxymethyl group per moleculeas the A, B, X and Y substituents.

EXAMPLE 3

A quantity (15.2 g, 0.1 mole) of1(2),4(5)bis[aminomethyl]bicyclo(2,2,1)heptane was placed into astainless steel beaker and 50 ml of distilled water was added, followedby the addition 37 ml of 50% NaOH. This solution was heated to ˜70° C.with stirring and carboxymethylation accomplished by adding dropwise58.9 g of 38% glycolonitrile while still heating, over a one-hourperiod. After ˜15 minutes of the addition, the temperature was at refluxand NH₃ was being liberated. Distilled water was added periodically toreplace the evaporated water. After completing the addition ofglycolonitrile, the solution was heated for an additional hour whilestirring and purging with N₂. The compound formed was thetetracarboxymethyl derivative wherein A, B, X and Y are CH₂ --COONa.

The utility of the compounds of the invention was ascertained byconducting scale inhibition tests according to National Association ofCorrosion Engineers (NACE) test method TM-03-74. The calcium carbonatescale inhibition results are shown in Table I and compared with acommercially available scale inhibitor, aminotri(methylenephosphonicacid). Calcium sulfate scale inhibition was also tested and results areshown in Table II.

                  TABLE I                                                         ______________________________________                                        Calcium Carbonate Scale Inhibition Data                                                         % of Ca.sup.++  Remaining                                                     in Solution at                                              Compound    Concentration*                                                                            24 Hrs  48 Hrs                                                                              72 Hrs                                  ______________________________________                                        None        --          54      53    52                                      Example 1   10 ppm      96      94    86                                      Example 2   10 ppm      94      82    79                                      aminotri(methylene-                                                                       10 ppm      94      82    79                                      phosphonic acid)                                                              ______________________________________                                    

                  TABLE II                                                        ______________________________________                                        Calcium Sulfate Scale Inhibition Data                                                           % of Ca.sup.++  Remaining                                                     in Solution at                                              Compound    Concentration*                                                                            24 Hrs  48 Hrs                                                                              72 Hrs                                  ______________________________________                                        None        --          67      65    65                                      Example 1   1 ppm       100     99    99                                      Example 2   1 ppm       99      99    98                                      aminotri(methylene-                                                                       1 ppm       84      80    77                                      phosphonic acid)                                                              ______________________________________                                    

The usefulness of the compounds of the present invention to act aschelating agents was demonstrated by titrating the compounds withstandard copper solution in the presence of chrome azurol-S indicator.The compound of Example 1 was titrated and found to complexapproximately 1.5 moles of copper per mole of ligand. This compound canfunction as either a threshold compound or a chelating agent.

It should be recognized that the compounds of the invention can haveseveral different groups as the A, B, X and Y substituents on the samemolecule, but that when mixed derivatives are obtained, it is notusually possible to direct or predict which amine hydrogens aresubstituted. The product, in all probability, contains a mixture ofisomeric compounds.

While all of the compounds will chelate metal ions, only those whichcontain at least one methylenephosphonic acid group or its salt willprovide a threshold effect.

I claim:
 1. A process for inhibiting the precipitation of scaleproducing metal ions from their aqueous solutions which comprises addingto said solutions in less than stoichiometric amounts, based on themetal ions present, an effective amount of compound of the formula##STR7## wherein substituents A, B, X and Y each are independentlyselected from radicals consisting of hydrogen, hydroxyalkyl (wherein thealkyl group contains 2-6 carbon atoms), methylenephosphonic; methylene-,ethylene- and propylenesulfonic; 2-hydroxypropylsulfonic;alkylcarboxylic acid radicals (having 2-4 carbon atoms) and the alkali,alkaline earth metal, ammonium and amine salts thereof and wherein atleast one of said substituents is a methylenephosphonic acid radical ora salt thereof.
 2. The process of claim 1 wherein the substituent saltof the methylenephosphonic acid radical is an alkali metal salt.
 3. Theprocess of claim 1 wherein the substituent salt of themethylenephosphonic acid is an amine salt.
 4. The process of claim 1wherein the substituent salt of the methylenephosphonic acid is analkaline earth metal salt.
 5. The process of claim 4 wherein thealkaline earth metal is magnesium, calcium or barium.
 6. The process ofclaim 1 wherein the substituent salt of the methylenephosphonic acid isan ammonium salt.